A low-speed two-wheel charging device and charging short-circuit protection circuit thereof

Abstract

The present invention provides a low-speed two-wheel charging device and a charging short-circuit protection circuit thereof, belonging to the field of electrical control and circuit protection, wherein the charging short-circuit protection circuit comprises: a short-circuit current acquisition circuit for acquiring the AC current in the main charging circuit of the low-speed two-wheel charging device and for converting it into a DC voltage; a window comparator circuit for detecting whether the DC voltage is between two predetermined threshold levels and outputting a corresponding level; a charging circuit switch protection circuit, which is an electronic short-circuit protection circuit, for protecting the charging of the low-speed two-wheel charging device; a digital logic control circuit, which is connected to the output end of the window comparator circuit and to the charging circuit switch protection circuit, for controlling the on and off of the charging circuit switch protection circuit based on the level output by the window comparator circuit. The present invention can avoid using a traditional mechanical short-circuit protection device to realize charging short-circuit protection, reduce the volume of the protection device, and increase the response to faults.

Description

Technical Field

[0001] The present invention relates to the field of electrical control and circuit protection, and in particular to a low-speed two-wheel charging device and a charging short-circuit protection circuit thereof. Background Art

[0002] In recent years, with the rapid development of electrical science and technology, especially in the field of low-speed two-wheel charging equipment (such as low-speed two-wheel charging piles, low-speed two-wheel electric vehicle chargers, etc.), rapid technological development has been achieved. In order to meet people's daily travel needs and the charging needs of vehicle equipment, in the vehicle charging technology of low-speed two-wheel electric vehicles, the requirements for power safety are becoming higher and higher, especially the requirements for the charging short-circuit protection function of low-speed two-wheel charging equipment are also becoming higher and higher.

[0003] However, the charging short-circuit protection function of low-speed two-wheel charging equipment on the market is usually implemented by traditional mechanical short-circuit protection devices such as circuit breakers. The use of traditional mechanical short-circuit protection devices to achieve charging short-circuit protection is not only large in size, but also slow to respond to faults, and cannot meet the performance requirements of fast sensitivity of equipment protection. It is impossible to respond in time to achieve effective protection, which can easily cause the subsequent equipment and protection to trip, and easily affect the charging equipment or the environment, expanding the scope of the hazard area. Summary of the invention

[0004] The object of the present invention is to provide a low-speed two-wheel charging device and a charging short-circuit protection circuit thereof to solve at least one of the above problems.

[0005] In a first aspect, the technical solution of the present invention provides a charging short-circuit protection circuit for a low-speed two-wheel charging device, including a short-circuit current acquisition circuit, a window comparator circuit, a digital logic control circuit and a charging circuit switch protection circuit;

[0006] The short-circuit current collection circuit is used to collect the AC current in the main charging circuit of the low-speed two-wheel charging device, and to convert the collected AC current into a DC voltage;

[0007] A window comparator circuit is connected to the output end of the short-circuit current acquisition circuit, and is used to detect whether the DC voltage is between two predetermined threshold levels. If the detection result is no, a low level is output, and if the detection result is yes, a high level is output; the two threshold levels are the maximum and minimum values ​​of the overcurrent value of the AC charging voltage during the normal charging process of the main charging circuit of the low-speed two-wheel charging device;

[0008] The charging circuit switch protection circuit is an electronic short-circuit protection circuit used to protect the charging of low-speed two-wheel charging equipment;

[0009] The digital logic control circuit has an input end connected to the output end of the window comparator circuit, and an output end connected to the charging circuit switch protection circuit. It is used to realize on and off control of the charging circuit switch protection circuit based on the level output by the window comparator circuit, and to realize the function of maintaining the level output by the digital logic control circuit, so as to realize charging short-circuit protection for low-speed two-wheel charging equipment.

[0010] Further, the short-circuit current collection circuit includes an input terminal;

[0011] The input end of the short-circuit current acquisition circuit includes a sampling current inflow end IN+ and a sampling current outflow end IN-; the short-circuit current acquisition circuit is used to be connected in series to the live wire of the main charging circuit of the low-speed two-wheel charging device through the sampling current inflow end IN+ and the sampling current outflow end IN-;

[0012] The short-circuit current collection circuit also includes a current collection chip U1 and a rectifier filter circuit;

[0013] The positive input terminal of the current acquisition chip U1 is connected to the sampling current inflow terminal IN+;

[0014] The negative input terminal of the current acquisition chip U1 is connected to the sampling current outflow terminal IN- through the charging circuit switch protection circuit;

[0015] The current acquisition chip U1 is used to collect the AC current in the main charging circuit of the low-speed two-wheel charging device;

[0016] The input end of the rectifier and filter circuit is connected to the output end of the current acquisition chip U1, and is used to rectify and filter the current collected by the current acquisition chip U1 into a DC voltage;

[0017] The output end of the rectifier and filter circuit is connected to the input end of the window comparator circuit.

[0018] Furthermore, the current acquisition chip U1 adopts a Hall current sensor chip, the IP+ pin of the Hall current sensor chip is the positive input terminal, the IP- pin of the Hall current sensor chip corresponds to the negative input terminal, the IP+ pin of the Hall current sensor chip is connected to the sampling current inflow terminal IN+, and the IP- pin of the Hall current sensor chip is connected to the sampling current outflow terminal IN- through the charging circuit switch protection circuit; the VIOUT pin of the Hall current sensor chip corresponds to the output terminal of the current acquisition chip U1;

[0019] The rectifier and filter circuit includes a first resistor R1, a second resistor R2, a fifth resistor R5, a first diode D1 and a first capacitor C1. The first end of the first resistor R1 is connected to the VIOUT pin of the Hall current sensor chip, the second end of the first resistor R1 is respectively connected to the first end of the second resistor R2 and the anode of the first diode D1, the cathode of the first diode D1 is respectively connected to the first end of the fifth resistor R5 and the first end of the first capacitor C1, the second end of the first capacitor C1 and the second end of the second resistor R2 are both grounded, the second end of the fifth resistor R5 is the output end of the short-circuit current acquisition circuit, and the second end of the fifth resistor R5 is connected to the input end of the window comparator circuit.

[0020] Further, the window comparator circuit includes a first operational amplifier U2A and a second operational amplifier U2B;

[0021] The non-inverting input terminal of the first operational amplifier U2A is connected to the output terminal of the short-circuit current collection circuit;

[0022] The inverting input terminal of the first operational amplifier U2A is connected to a first threshold level setting circuit; the first threshold level setting circuit is used to provide a first threshold level to the inverting input terminal of the first operational amplifier U2A;

[0023] The inverting input terminal of the second operational amplifier U2B is connected to the output terminal of the short-circuit current collection circuit;

[0024] The non-inverting input terminal of the second operational amplifier U2B is connected to a second threshold level setting circuit; the second threshold level setting circuit is used to provide a second threshold level to the non-inverting input terminal of the second operational amplifier U2B;

[0025] The output end of the first operational amplifier U2A is connected to the output end of the second operational amplifier U2B to form the output end of the window comparator circuit;

[0026] The first threshold level and the second threshold level are the two predetermined threshold levels, wherein the first threshold level is smaller than the second threshold level.

[0027] Furthermore, the digital logic control circuit includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an optocoupler chip U3, a JK trigger chip U4 and a reset button SW1; the first end of the eighth resistor R8 and the first end of the ninth resistor R9 are both connected to the VCC power supply; the second end of the eighth resistor R8 and the output end of the window comparator circuit are both connected to pin 2 of the optocoupler chip U3, the second end of the ninth resistor R9 is connected to pin 1 of the optocoupler chip U3, pin 3 of the optocoupler chip U3 is grounded, and pin 4 of the optocoupler chip U3 is connected in series with the tenth pin The resistor R10 is connected to the VCC power supply, the 4th pin of the optocoupler chip U3 is connected to the CLK1 pin of the JK trigger chip U4, the K1 pin, J1 pin, PR1 pin and VDD pin of the JK trigger chip U4 are all connected to the VCC power supply, the CLR1 pin of the JK trigger chip U4 is connected in series with the reset button SW1 and then grounded, the GND pin of the JK trigger chip U4 is grounded, and the Q1 pin of the JK trigger chip U4 is connected to the charging circuit switch protection circuit to realize the on and off control of the charging circuit switch protection circuit.

[0028] Further, the charging circuit switch protection circuit includes a second switch protection circuit;

[0029] The second switch protection circuit includes an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a fourth capacitor C4, a bidirectional thyristor Q4, a thyristor optocoupler U5 and a third transistor Q3; the bidirectional thyristor Q4 is connected in series between the negative input terminal of the current acquisition chip U1 and the sampling current outflow terminal IN- through its first main terminal T1 and second main terminal T2, the second main terminal T2 of the bidirectional thyristor Q4 is connected to the negative input terminal of the current acquisition chip U1, the first main terminal T1 of the bidirectional thyristor Q4 is connected to the sampling current outflow terminal IN-, the first main terminal T1 of the bidirectional thyristor Q4 is connected in series with the eleventh resistor R11 and the fourth capacitor C4 in sequence, and then connected to the bidirectional thyristor Q4. The second main terminal T2 of the bidirectional thyristor Q4 is connected to the first main terminal T1 of the bidirectional thyristor Q4 after being connected in series with the thirteenth resistor R13, the thyristor of the thyristor optocoupler U5, and the twelfth resistor R12 in sequence. The control end of the bidirectional thyristor Q4 is connected to the connection line between the thyristor optocoupler U5 and the twelfth resistor R12. The photodiode of the thyristor optocoupler U5 is connected in series between VCC and the collector of the third triode Q3. The base of the third triode Q3 is connected to the first end of the fourteenth resistor R14 and the first end of the fifteenth resistor R15. The second end of the fifteenth resistor R15 and the emitter of the third triode Q3 are both grounded. The second end of the fourteenth resistor R14 is connected to the output end of the digital logic control circuit.

[0030] Further, the charging circuit switch protection circuit also includes a first switch protection circuit;

[0031] The first switch protection circuit includes an electromagnetic relay RL1, a second diode D2, a second transistor Q2, a sixteenth resistor R16 and a seventeenth resistor R17. Pins 3 and 4 of the electromagnetic relay RL1 are connected in series between the second main terminal T2 of the bidirectional thyristor Q4 and the negative input terminal of the current acquisition chip U1. Pin 3 of the electromagnetic relay RL1 is connected to the negative input terminal of the current acquisition chip U1. Pin 4 of the electromagnetic relay RL1 is connected to the second main terminal T2 of the bidirectional thyristor Q4. Pin 2 of the electromagnetic relay RL1 is respectively connected to the first end of the second diode D2 and VCC. The second end of the second diode D2 and the collector of the second transistor Q2 are both connected to pin 1 of the electromagnetic relay RL1. The base of the second transistor Q2 is respectively connected to the first end of the sixteenth resistor R16 and the first end of the seventeenth resistor R17. The second end of the seventeenth resistor R17 and the emitter of the second transistor Q2 are both grounded. The second end of the sixteenth resistor R16 is connected to the output end of the digital logic control circuit.

[0032] Furthermore, the input end of the short-circuit current collection circuit also includes an input terminal H1, which has pin 1 and pin 2. Pin 1 of the input terminal H1 is connected to the sampling current outflow terminal IN-, and pin 2 of the input terminal H1 is connected to the sampling current inflow terminal IN+.

[0033] In a second aspect, the present invention provides a low-speed two-wheel charging device, which is equipped with the charging short-circuit protection circuit described in the above aspects.

[0034] Furthermore, the low-speed two-wheeled charging equipment is any one of a low-speed two-wheeled charging pile, a low-speed two-wheeled electric vehicle charger, and a low-speed two-wheeled electric vehicle mobile charging vehicle.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The charging circuit switch protection circuit adopted in the present invention is an electronic short-circuit protection circuit, which can avoid the use of traditional mechanical short-circuit protection equipment for charging short-circuit protection of low-speed two-wheel charging equipment. This helps to solve the problem of large size of protection equipment to a certain extent, and also helps to increase fault response. To a certain extent, it helps to achieve the performance requirements of fast sensitivity of equipment protection, and timely responds to actions to achieve effective protection, which helps to avoid causing tripping of subsequent equipment and protection to a certain extent, avoid affecting the charging equipment or the environment, and reduce hazards.

[0037] In addition, the charging circuit switch protection circuit used in the present invention includes a second switch protection circuit, which uses a bidirectional thyristor to achieve the function of removing the charging short circuit fault. The fast response characteristics of the thyristor help to achieve the rapid removal of the charging short circuit fault.

[0038] In addition, the charging circuit switch protection circuit used in the present invention also includes a first switch protection circuit. The first switch protection circuit uses an electromagnetic relay to realize the function of cutting off the charging short circuit fault. The first switch protection circuit and the second switch protection circuit cooperate with each other, so that the present invention can not only use the fast response characteristics of the thyristor to solve the relatively slow response characteristics of the single use of electromagnetic relays, but also use the characteristics of the electromagnetic relay that can completely isolate and cut off the fault electrically, cut off the leakage current formed in the circuit after the thyristor is disconnected, and achieve the purpose of completely and quickly cutting off the fault, thereby reducing the harm to personal safety. In addition, the first switch protection circuit and the second switch protection circuit can also be used as a two-way standby control, which helps to strengthen the protection of the charging circuit.

[0039] The digital logic control circuit of the present invention is implemented based on a JK trigger chip, utilizing the characteristic of the JK trigger forming a T trigger, and using the falling edge of the clock CLK of the JK trigger to trigger, which not only helps to assist in avoiding the use of traditional mechanical short-circuit protection equipment to implement charging short-circuit protection for low-speed two-wheel charging equipment, but also helps to utilize the output level holding function of the JK trigger chip to avoid the window comparator circuit outputting a high level again to close the charging loop switch protection circuit and form a fault oscillation circuit when the protection circuit has not yet cut off the short-circuit fault.

[0040] The invention has reliable design principle, simple structure and very broad application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 is a schematic block diagram of a charging short-circuit protection circuit according to an embodiment of the present invention;

[0043] Figure 2 is a schematic circuit diagram of a charging short-circuit protection circuit according to an embodiment of the present invention;

[0044] Figure 3 is a schematic circuit diagram of a charging short-circuit protection circuit according to another embodiment of the present invention;

[0045] Figure 4 A schematic block diagram of a low-speed two-wheel charging device according to an embodiment of the present invention;

[0046] Figure 5An exemplary circuit block diagram of an integrated charging short-circuit protection circuit in a low-speed two-wheel charging pile;

[0047] Figure 6 Another exemplary circuit block diagram of an integrated charging short-circuit protection circuit in a low-speed two-wheel charging pile. DETAILED DESCRIPTION

[0048] The core of the present invention is to provide a low-speed two-wheel charging device and a charging short-circuit protection circuit thereof, so as to solve the problem that the prior art uses traditional mechanical short-circuit protection equipment to achieve charging short-circuit protection. Not only is the equipment bulky, but it also reacts slowly to faults, and cannot meet the performance requirements of fast sensitivity of equipment protection. It cannot respond in time to achieve effective protection, which easily causes the subsequent equipment and protection to trip, easily affects the charging equipment or the environment, and expands the scope of the hazard area.

[0049] To make the technical solution and advantages of the present invention more clear, the technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0050] The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0052] In addition, it should be noted that the terms "first", "second", etc. used in the present invention to limit the corresponding parts are only for the convenience of distinguishing the corresponding parts. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0053] The technical solution of the present invention will be introduced and explained below through several embodiments.

[0054] In one embodiment, the present invention provides a charging short-circuit protection circuit for a low-speed two-wheel charging device, the charging short-circuit protection circuit comprising a short-circuit current acquisition circuit, a window comparator circuit, a digital logic control circuit and a charging circuit switch protection circuit. Figure 1 shown.

[0055] The short-circuit current collection circuit is used to collect the AC current in the main charging circuit of the low-speed two-wheel charging equipment, and to convert the collected AC current into a DC voltage.

[0056] The window comparator circuit is connected to the output end of the short-circuit current acquisition circuit and is used to detect whether the DC voltage is between two predetermined threshold levels. If the detection result is no, a low level is output; if the detection result is yes, a high level is output.

[0057] The two predetermined threshold levels are the maximum and minimum values ​​of the overcurrent value of the AC charging voltage during normal charging of the main charging circuit of the low-speed two-wheel charging device.

[0058] The charging circuit switch protection circuit is an electronic short-circuit protection circuit used to protect the charging of low-speed two-wheel charging equipment.

[0059] The digital logic control circuit has an input end connected to the output end of the window comparator circuit, and an output end connected to the charging circuit switch protection circuit. It is used to realize on and off control of the charging circuit switch protection circuit based on the level output by the window comparator circuit, and to realize the function of maintaining the level output by the digital logic control circuit, so as to realize charging short-circuit protection for low-speed two-wheel charging equipment.

[0060] In this embodiment, when the low-speed two-wheel charging device is short-circuited during charging, the digital logic control circuit can control the charging circuit switch protection circuit to be disconnected to cut off the short-circuit current. When the low-speed two-wheel charging device is charging normally, the digital logic control circuit can control the charging circuit switch protection circuit to be turned on. Then, charging protection for the low-speed two-wheel charging device is realized.

[0061] It can be understood that the level output by the output end of the window comparator circuit is the short-circuit judgment level. If the short-circuit judgment level output by the window comparator circuit is a low level, it indicates that there is a short-circuit current in the charging circuit. That is, if the short-circuit judgment level output by the window comparator circuit is a high level, it indicates that there is no short-circuit current in the charging circuit.

[0062] The present invention adopts an electronic short-circuit protection device, avoiding the use of traditional mechanical short-circuit protection devices, solving the problem of large size of the protection device to a certain extent, and increasing the response to faults, ensuring the performance requirements of rapid sensitivity of equipment protection to a certain extent, and facilitating timely action response to achieve effective protection, thereby avoiding to a certain extent the tripping of subsequent equipment and protection, avoiding to a certain extent the impact on charging equipment or the environment, and helping to reduce hazards to a certain extent.

[0063] Optionally, the short-circuit current acquisition circuit includes an input terminal, which includes a sampling current inflow terminal IN+ and a sampling current outflow terminal IN-. The sampling current inflow terminal IN+ and the sampling current outflow terminal IN- are used for the inflow and outflow of the sampling current.

[0064] The short-circuit current acquisition circuit is used to be connected in series in the live wire of the main charging circuit of the low-speed two-wheel charging device through the sampling current inflow terminal IN+ and the sampling current outflow terminal IN-.

[0065] Optionally, the short-circuit current collection circuit further includes a current collection chip U1 and a rectifier and filter circuit;

[0066] The positive input terminal of the current acquisition chip U1 is connected to the sampling current inflow terminal IN+;

[0067] The negative input terminal of the current acquisition chip U1 is connected to the sampling current outflow terminal IN- through the charging circuit switch protection circuit;

[0068] The current acquisition chip U1 is used to collect the AC current in the main charging circuit of the low-speed two-wheel charging device;

[0069] The input end of the rectifier and filter circuit is connected to the output end of the current acquisition chip U1, and is used to rectify and filter the current collected by the current acquisition chip U1 into a DC voltage;

[0070] The output end of the rectifier and filter circuit is connected to the input end of the window comparator circuit. Figure 2 shown.

[0071] In this embodiment, the current acquisition chip U1 adopts a Hall current sensor chip, the IP+ pin of the Hall current sensor chip is the positive input terminal, the IP- pin of the Hall current sensor chip corresponds to the negative input terminal, the IP+ pin of the Hall current sensor chip is connected to the sampling current inflow terminal IN+, the IP- pin of the Hall current sensor chip is connected to the sampling current outflow terminal IN- through the charging circuit switch protection circuit, the VIOUT pin of the Hall current sensor chip corresponds to the output terminal of the current acquisition chip U1, the power pin of the Hall current sensor chip is connected to VCC, and the GND pin of the Hall current sensor chip is grounded. Figure 2 shown.

[0072] like Figure 2As shown, in this embodiment, the rectifier and filter circuit includes a first resistor R1, a second resistor R2, a fifth resistor R5, a first diode D1 and a first capacitor C1. The first end of the first resistor R1 is connected to the VIOUT pin of the Hall current sensor chip, the second end of the first resistor R1 is respectively connected to the first end of the second resistor R2 and the anode of the first diode D1, the cathode of the first diode D1 is respectively connected to the first end of the fifth resistor R5 and the first end of the first capacitor C1, the second end of the first capacitor C1 and the second end of the second resistor R2 are both grounded, the second end of the fifth resistor R5 is the output end of the short-circuit current acquisition circuit, and the second end of the fifth resistor R5 is connected to the input end of the window comparator circuit.

[0073] The short-circuit current collection circuit of the present invention adopts a non-contact electrical isolation Hall sensor and an RC rectifier filter circuit to collect the current of the main circuit and perform smoothing filtering on the collected current.

[0074] In this embodiment, the Hall sensor chip integrates a sampling circuit and a level boosting circuit, and can output a 1.7V-3.4V DC signal through its VIOUT pin for use by the subsequent comparator circuit. When in use, the current in the main charging circuit of the low-speed two-wheel charging device flows into the sampling circuit in the Hall sensor chip through the sampling current inflow terminal IN+, and then flows out through the sampling current outflow terminal IN-.

[0075] During specific implementation, those skilled in the art may select other corresponding current acquisition chips and rectifier filter circuits from the prior art to implement the short-circuit current acquisition circuit of the present invention according to actual conditions.

[0076] Optionally, the window comparator circuit includes a first operational amplifier U2A and a second operational amplifier U2B.

[0077] Please refer to Figure 2 The non-inverting input terminal of the first operational amplifier U2A is connected to the output terminal of the short-circuit current acquisition circuit, the inverting input terminal of the first operational amplifier U2A is connected to a first threshold level setting circuit, the first threshold level setting circuit is used to provide a first threshold level to the inverting input terminal of the first operational amplifier U2A, the inverting input terminal of the second operational amplifier U2B is connected to the output terminal of the short-circuit current acquisition circuit, the non-inverting input terminal of the second operational amplifier U2B is connected to a second threshold level setting circuit, the second threshold level setting circuit is used to provide a second threshold level to the non-inverting input terminal of the second operational amplifier U2B, the output terminal of the first operational amplifier U2A is connected to the output terminal of the second operational amplifier U2B to form the output terminal of the window comparator circuit.

[0078] Among them, the first threshold level and the second threshold level are the two pre-given threshold levels, wherein the first threshold level is the minimum value of the overcurrent value of the AC charging voltage during the normal charging process of the main charging circuit of the low-speed two-wheel charging device, and the second threshold level is the maximum value of the overcurrent value of the AC charging voltage during the normal charging process of the main charging circuit of the low-speed two-wheel charging device, and the first threshold level is less than the second threshold level.

[0079] In this embodiment, the first threshold level setting circuit includes a third resistor R3, a fourth resistor R4 and a second capacitor C2, the first end of the third resistor R3 is connected to the VCC power supply, the second end of the third resistor R3 is respectively connected to the first end of the fourth resistor R4, the first end of the second capacitor C2 and the inverting input end of the first operational amplifier U2A, and the second end of the fourth resistor R4 and the second end of the second capacitor C2 are both grounded.

[0080] In this embodiment, the second threshold level setting circuit includes a sixth resistor R6, a seventh resistor R7 and a third capacitor C3, the first end of the sixth resistor R6 is connected to the VCC power supply, the second end of the sixth resistor R6 is respectively connected to the first end of the seventh resistor R7, the first end of the third capacitor C3 and the in-phase input end of the second operational amplifier U2B, and the second end of the seventh resistor R7 and the second end of the third capacitor C3 are both grounded.

[0081] The first operational amplifier U2A and the second operational amplifier U2B form a window comparator. The positive power supply pin of the first operational amplifier U2A is connected to VCC, and the ground pin of the first operational amplifier U2A is grounded.

[0082] In specific implementation, those skilled in the art may set the resistance values ​​of the third resistor R3, the fourth resistor R4, the sixth resistor R6, and the seventh resistor R7 based on experience so that the two threshold levels output by the first threshold level setting circuit and the second threshold level setting circuit are the two threshold levels of the window comparator circuit (i.e., the two pre-given threshold levels).

[0083] As an illustrative embodiment of the present invention, the digital logic control circuit includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an optocoupler chip U3, a JK trigger chip U4 and a reset button SW1; the first end of the eighth resistor R8 and the first end of the ninth resistor R9 are both connected to the VCC power supply; the second end of the eighth resistor R8 and the output end of the window comparator circuit are both connected to pin 2 of the optocoupler chip U3, the second end of the ninth resistor R9 is connected to pin 1 of the optocoupler chip U3, the 3rd pin of the optocoupler chip U3 is grounded, and the 4th pin of the optocoupler chip U3 is grounded. The pin is connected in series with the tenth resistor R10 and then connected to the VCC power supply, the 4 pin of the optocoupler chip U3 is connected to the CLK1 pin of the JK trigger chip U4, the K1 pin, J1 pin, PR1 pin and VDD pin of the JK trigger chip U4 are all connected to the VCC power supply, the CLR1 pin of the JK trigger chip U4 is connected in series with the reset button SW1 and then grounded, the GND pin of the JK trigger chip U4 is grounded, and the Q1 pin of the JK trigger chip U4 is connected to the charging circuit switch protection circuit to realize the on and off control of the charging circuit switch protection circuit.

[0084] The reset button SW1 is used for the reset control of the JK trigger chip U4.

[0085] The digital logic control circuit realizes the output level holding function through the JK flip-flop chip.

[0086] The present invention utilizes the characteristic of a JK trigger forming a T trigger, adopts the falling edge trigger of the clock CLK of the JK trigger, utilizes the characteristic of a window comparator circuit that changes the output level from a high level to a low level when a short-circuit fault current is detected, triggers the JK trigger level to flip, outputs a low level, and controls the disconnection of a subsequent charging loop switch protection circuit.

[0087] The use of the JK trigger (with a signal holding function) in the present invention helps to avoid the situation where the window comparator circuit has formed a normal level signal again (i.e., the window comparator circuit outputs a high level again) before the protection circuit has cut off the short circuit fault, causing the closed charging loop switch protection circuit to form a fault oscillation circuit.

[0088] In this embodiment, pin 1 of the optocoupler chip U3 is the anode end of the optical transmitter of the optocoupler chip U3, pin 2 of the optocoupler chip U3 is the cathode end of the optical transmitter of the optocoupler chip U3, pin 4 of the optocoupler chip U3 is the anode end of the optical receiver of the optocoupler chip U3, and pin 3 of the optocoupler chip U3 is the cathode end of the optical receiver of the optocoupler chip U3.

[0089] In this embodiment, the charging circuit switch protection circuit includes a first switch protection circuit and a second switch protection circuit.

[0090] The second switch protection circuit includes an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a fourth capacitor C4, a bidirectional thyristor Q4, a thyristor optocoupler U5 and a third transistor Q3; the bidirectional thyristor Q4 is connected in series between the negative input terminal of the current acquisition chip U1 and the sampling current outflow terminal IN- through its first main terminal T1 and the second main terminal T2, the second main terminal T2 of the bidirectional thyristor Q4 is connected to the negative input terminal of the current acquisition chip U1, and the bidirectional thyristor Q4 The first main terminal T1 is connected to the sampling current outflow terminal IN-, the first main terminal T1 of the bidirectional thyristor Q4 is connected in series with the eleventh resistor R11 and the fourth capacitor C4 in sequence, and then connected to the second main terminal T2 of the bidirectional thyristor Q4, the second main terminal T2 of the bidirectional thyristor Q4 is connected in series with the thirteenth resistor R13, the thyristor of the thyristor optocoupler U5, and the twelfth resistor R12 in sequence, and then connected to the first main terminal T1 of the bidirectional thyristor Q4, and the control terminal G of the bidirectional thyristor Q4 is connected to the connection line between the thyristor optocoupler U5 and the twelfth resistor R12 (as shown in FIG. Figure 2 As shown, the 6th pin of the thyristor optocoupler U5 is connected to the 13th resistor R13, and the 4th pin of the thyristor optocoupler U5 is respectively connected to the 12th resistor R12 and the control end G of the bidirectional thyristor Q4), the photodiode of the thyristor optocoupler U5 is connected in series between the VCC power supply and the collector of the third transistor Q3 (that is, the 1st pin of the thyristor optocoupler U5 is connected to the VCC power supply, and the 2nd pin of the thyristor optocoupler U5 is connected to the collector of the third transistor Q3), the base of the third transistor Q3 is connected to the first end of the fourteenth resistor R14 and the first end of the fifteenth resistor R15, the second end of the fifteenth resistor R15 and the emitter of the third transistor Q3 are both grounded, and the second end of the fourteenth resistor R14 is connected to the Q1 pin of the JK trigger chip U4. The thyristor optocoupler U5 works to drive the bidirectional thyristor Q4 in the main circuit, and a current path is formed between the first main terminal T1 and the second main terminal T2 as long as there is voltage.

[0091] In this embodiment, the photodiode of the thyristor optocoupler U5 is a light emitting diode, such as Figure 2 As shown, the anode of the light emitting diode is connected to VCC, and the cathode is connected to the collector of the third triode Q3. In specific implementation, the photodiode of the thyristor optocoupler U5 can also be a photosensitive diode.

[0092] The first switch protection circuit includes an electromagnetic relay RL1, a second diode D2, a second transistor Q2, a sixteenth resistor R16 and a seventeenth resistor R17. Pins 3 and 4 of the electromagnetic relay RL1 are connected in series between the second main terminal T2 of the bidirectional thyristor Q4 and the negative input terminal of the current acquisition chip U1. Pin 3 of the electromagnetic relay RL1 is connected to the negative input terminal of the current acquisition chip U1. Pin 4 of the electromagnetic relay RL1 is connected to the second main terminal T2 of the bidirectional thyristor Q4. Pin 2 of the electromagnetic relay RL1 is respectively connected to the first end of the second diode D2 and VCC. The second end of the second diode D2 and the collector of the second transistor Q2 are both connected to pin 1 of the electromagnetic relay RL1. The base of the second transistor Q2 is respectively connected to the first end of the sixteenth resistor R16 and the first end of the seventeenth resistor R17. The second end of the seventeenth resistor R17 and the emitter of the second transistor Q2 are both grounded. The second end of the sixteenth resistor R16 is connected to the Q1 pin of the JK trigger chip U4.

[0093] When the present invention is used:

[0094] (1) When the window comparator circuit outputs a high level (corresponding to charging without short circuit), the optocoupler chip U3 is not turned on. At this time, since the JK trigger is triggered at the falling edge of the clock CLK, the Q1 pin of the JK trigger chip U4 outputs a high level, resulting in:

[0095] On the one hand, the second transistor Q2 is turned on, the coil of the electromagnetic relay RL1 (pin 1 and pin 2 of the electromagnetic relay RL1 correspond to the two ends of the coil of the electromagnetic relay RL1) is energized, the normally open contact of the electromagnetic relay RL1 (i.e., the contact corresponding to pin 3 and pin 4 of the electromagnetic relay RL1) is closed, and the first switch protection circuit is turned on;

[0096] On the other hand, the third transistor Q3 is turned on, the third transistor Q3 is turned on to control the thyristor optocoupler U5 to be turned on, the thyristor optocoupler U5 is turned on to control the bidirectional thyristor Q4 to be turned on, and then the second switch protection circuit is turned on.

[0097] (2) When the window comparator circuit outputs a low level (corresponding to a short circuit in the charging), the optocoupler chip U3 is turned on. Since the JK trigger is triggered at the falling edge of the clock CLK, the Q1 pin of the JK trigger chip U4 outputs a low level at this time, resulting in:

[0098] On the one hand, the second transistor Q2 is not conducting, the coil of the electromagnetic relay RL1 (pin 1 and pin 2 of the electromagnetic relay RL1 correspond to the two ends of the coil of the electromagnetic relay RL1) loses power, the normally open contact of the electromagnetic relay RL1 (i.e., the contact corresponding to pin 3 and pin 4 of the electromagnetic relay RL1) opens, and the first switch protection circuit is disconnected;

[0099] On the other hand, the third transistor Q3 is not conducting, which cuts off the conduction of the thyristor optocoupler U5, which cuts off the conduction of the bidirectional thyristor Q4, thereby disconnecting the second switch protection circuit.

[0100] When the JK trigger chip U4 needs to be reset after the charging short circuit problem is solved, press the reset button SW1 to reset the JK trigger chip U4. After resetting, the Q1 pin of the JK trigger chip U4 outputs a high level. At this time, the first switch protection circuit and the second switch protection circuit are turned on and continue to be used for subsequent short circuit protection.

[0101] It can be understood that the Q1 pin of the JK trigger chip U4 is the output end of the digital logic control circuit.

[0102] As an exemplary embodiment of the present invention, Figure 3 As shown, the input end of the short-circuit current acquisition circuit also includes an input terminal H1, and the input terminal H1 has a 1 pin and a 2 pin. The 1 pin of the input terminal H1 is connected to the sampling current outflow terminal IN-, and the 2 pin of the input terminal H1 is connected to the sampling current inflow terminal IN+.

[0103] It can be understood that the input terminal H1 in this embodiment can be a connector.

[0104] When in use, there is no need to connect the short-circuit current collection circuit in series to the live wire of the charging circuit of the low-speed two-wheel charging device through the sampling current inflow terminal IN+ and the sampling current outflow terminal IN-. Instead, the short-circuit current collection circuit can be connected in series to the live wire of the charging circuit of the low-speed two-wheel charging device through the input terminal H1.

[0105] It can be understood that, in specific implementation, an input terminal H2 that can be plugged and used in conjunction with the input terminal H1 can be pre-arranged in series in the live wire of the main charging circuit of the low-speed two-wheel charging device. When in use, the input terminal H1 is plugged into the input terminal H2, that is, the short-circuit current collection circuit is connected in series to the charging circuit of the low-speed two-wheel charging device, which is convenient for wiring.

[0106] In another embodiment, the present invention provides a low-speed two-wheel charging device, which is equipped with the charging short-circuit protection circuit in any of the above embodiments. Figure 4 shown.

[0107] Among them, when the input end of the short-circuit current collection circuit of the charging short-circuit protection circuit does not include the input terminal H1, the short-circuit current collection circuit of the charging short-circuit protection circuit is connected in series to the live wire of the charging circuit of the low-speed two-wheel charging device through the sampling current inflow terminal IN+ and the sampling current outflow terminal IN-.

[0108] When the input end of the short-circuit current acquisition circuit of the provided charging short-circuit protection circuit includes the input terminal H1, an input terminal H2 that can be plugged and used in conjunction with the input terminal H1 is arranged in series in the live wire of the charging circuit of the low-speed two-wheel charging device, and the input terminal H2 is plug-connected to the input terminal H1.

[0109] In another embodiment, the low-speed two-wheel charging device in the present invention is a low-speed two-wheel charging pile.

[0110] Please refer to Figure 5 , Figure 5 This is an exemplary circuit principle block diagram of an integrated charging short-circuit protection circuit in a low-speed two-wheel charging pile. Figure 5 The charging short-circuit protection circuit integrated in the low-speed two-wheel charging pile does not have an input terminal H1. Figure 5 The charging interface in the vehicle is the charging interface provided by the low-speed two-wheel charging pile to the outside world.

[0111] Please refer to Figure 6 , Figure 6 This is another exemplary circuit principle block diagram of an integrated charging short-circuit protection circuit in a low-speed two-wheel charging pile. Figure 6 The charging short-circuit protection circuit integrated in the medium and low-speed two-wheel charging pile is equipped with an input terminal H1.

[0112] In another embodiment, the low-speed two-wheel charging device in the present invention is a low-speed two-wheel electric vehicle charger. The circuit principle block diagram of the integrated charging short-circuit protection circuit in the low-speed two-wheel electric vehicle charger can refer to the low-speed two-wheel charging pile. When it is implemented, it only needs to integrate the charging short-circuit protection circuit into the AC access end of the low-speed two-wheel electric vehicle charger (that is, it is necessary to connect the AC Figure 5 , Figure 6 The charging interface in the low-speed two-wheel electric vehicle charger is replaced with a plug for connecting to AC power) and ensure that the connected current flows into the sampling circuit of the charging short-circuit protection circuit through the sampling current inflow terminal IN+, and then flows out of the sampling circuit of the charging short-circuit protection circuit through the sampling current outflow terminal IN-.

[0113] In another embodiment, the low-speed two-wheel charging device in the present invention is a low-speed two-wheel electric vehicle mobile charging vehicle. The circuit principle block diagram of the integrated charging short-circuit protection circuit in the low-speed two-wheel electric vehicle mobile charging vehicle can refer to the low-speed two-wheel charging pile.

[0114] The same and similar parts between the various embodiments in this specification can be referenced to each other.

[0115] Although the present invention has been described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, and all of these shall be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A charging short-circuit protection circuit for a low-speed two-wheel charging device, characterized in that: It includes a short-circuit current acquisition circuit, a window comparator circuit, a digital logic control circuit and a charging circuit switch protection circuit; The short-circuit current collection circuit is used to collect the AC current in the main charging circuit of the low-speed two-wheel charging device, and to convert the collected AC current into a DC voltage; A window comparator circuit is connected to the output end of the short-circuit current acquisition circuit, and is used to detect whether the DC voltage is between two predetermined threshold levels, and if not, outputs a low level, and if so, outputs a high level; the two threshold levels are the maximum and minimum values ​​of the overcurrent value of the AC charging voltage during the normal charging process of the main charging circuit of the low-speed two-wheel charging device; The charging circuit switch protection circuit is an electronic short-circuit protection circuit used to protect the charging of low-speed two-wheel charging equipment; A digital logic control circuit, whose input end is connected to the output end of the window comparator circuit, and whose output end is connected to the charging circuit switch protection circuit, is used to realize on / off control of the charging circuit switch protection circuit based on the level output by the window comparator circuit, and to realize the function of maintaining the level output by the digital logic control circuit, so as to realize charging short-circuit protection for the low-speed two-wheel charging device; The short-circuit current collection circuit includes an input terminal; The input end of the short-circuit current acquisition circuit includes a sampling current inflow end IN+ and a sampling current outflow end IN-; the short-circuit current acquisition circuit is used to be connected in series to the live wire of the main charging circuit of the low-speed two-wheel charging device through the sampling current inflow end IN+ and the sampling current outflow end IN-; The short-circuit current collection circuit also includes a current collection chip U1 and a rectifier filter circuit; The positive input terminal of the current acquisition chip U1 is connected to the sampling current inflow terminal IN+; The negative input terminal of the current acquisition chip U1 is connected to the sampling current outflow terminal IN- through the charging circuit switch protection circuit; The current acquisition chip U1 is used to collect the AC current in the main charging circuit of the low-speed two-wheel charging device; The input end of the rectifier and filter circuit is connected to the output end of the current acquisition chip U1, and is used to rectify and filter the current collected by the current acquisition chip U1 into a DC voltage; The output end of the rectifier and filter circuit is connected to the input end of the window comparator circuit; The charging circuit switch protection circuit includes a second switch protection circuit; The second switch protection circuit includes an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a fourth capacitor C4, a bidirectional thyristor Q4, a thyristor optocoupler U5 and a third transistor Q3; the bidirectional thyristor Q4 is connected in series between the negative input terminal of the current acquisition chip U1 and the sampling current outflow terminal IN- through its first main terminal T1 and second main terminal T2, the second main terminal T2 of the bidirectional thyristor Q4 is connected to the negative input terminal of the current acquisition chip U1, the first main terminal T1 of the bidirectional thyristor Q4 is connected to the sampling current outflow terminal IN-, the first main terminal T1 of the bidirectional thyristor Q4 is connected in series with the eleventh resistor R11 and the fourth capacitor C4 in sequence, and then connected to the bidirectional thyristor Q4. The second main terminal T2 of the bidirectional thyristor Q4 is connected to the first main terminal T1 of the bidirectional thyristor Q4 after being connected in series with the thirteenth resistor R13, the thyristor of the thyristor optocoupler U5, and the twelfth resistor R12 in sequence. The control end of the bidirectional thyristor Q4 is connected to the connection line between the thyristor optocoupler U5 and the twelfth resistor R12. The photodiode of the thyristor optocoupler U5 is connected in series between VCC and the collector of the third transistor Q3. The base of the third transistor Q3 is connected to the first end of the fourteenth resistor R14 and the first end of the fifteenth resistor R15. The second end of the fifteenth resistor R15 and the emitter of the third transistor Q3 are both grounded. The second end of the fourteenth resistor R14 is connected to the output end of the digital logic control circuit. The charging circuit switch protection circuit also includes a first switch protection circuit; The first switch protection circuit includes an electromagnetic relay RL1, a second diode D2, a second transistor Q2, a sixteenth resistor R16 and a seventeenth resistor R17. Pins 3 and 4 of the electromagnetic relay RL1 are connected in series between the second main terminal T2 of the bidirectional thyristor Q4 and the negative input terminal of the current acquisition chip U1. Pin 3 of the electromagnetic relay RL1 is connected to the negative input terminal of the current acquisition chip U1. Pin 4 of the electromagnetic relay RL1 is connected to the second main terminal T2 of the bidirectional thyristor Q4. Pin 2 of the electromagnetic relay RL1 is respectively connected to the first end of the second diode D2 and VCC. The second end of the second diode D2 and the collector of the second transistor Q2 are both connected to pin 1 of the electromagnetic relay RL1. The base of the second transistor Q2 is respectively connected to the first end of the sixteenth resistor R16 and the first end of the seventeenth resistor R17. The second end of the seventeenth resistor R17 and the emitter of the second transistor Q2 are both grounded. The second end of the sixteenth resistor R16 is connected to the output end of the digital logic control circuit.

2. The charging short-circuit protection circuit according to claim 1, characterized in that: The current acquisition chip U1 adopts a Hall current sensor chip, the IP+ pin of the Hall current sensor chip is the positive input terminal, the IP- pin of the Hall current sensor chip corresponds to the negative input terminal, the IP+ pin of the Hall current sensor chip is connected to the sampling current inflow terminal IN+, and the IP- pin of the Hall current sensor chip is connected to the sampling current outflow terminal IN- through the charging circuit switch protection circuit; the VIOUT pin of the Hall current sensor chip corresponds to the output terminal of the current acquisition chip U1; The rectifier and filter circuit includes a first resistor R1, a second resistor R2, a fifth resistor R5, a first diode D1 and a first capacitor C1. The first end of the first resistor R1 is connected to the VIOUT pin of the Hall current sensor chip, the second end of the first resistor R1 is respectively connected to the first end of the second resistor R2 and the anode of the first diode D1, the cathode of the first diode D1 is respectively connected to the first end of the fifth resistor R5 and the first end of the first capacitor C1, the second end of the first capacitor C1 and the second end of the second resistor R2 are both grounded, the second end of the fifth resistor R5 is the output end of the short-circuit current acquisition circuit, and the second end of the fifth resistor R5 is connected to the input end of the window comparator circuit.

3. The charging short-circuit protection circuit according to claim 1, characterized in that: A window comparator circuit, comprising a first operational amplifier U2A and a second operational amplifier U2B; The non-inverting input terminal of the first operational amplifier U2A is connected to the output terminal of the short-circuit current collection circuit; The inverting input terminal of the first operational amplifier U2A is connected to a first threshold level setting circuit; the first threshold level setting circuit is used to provide a first threshold level to the inverting input terminal of the first operational amplifier U2A; The inverting input terminal of the second operational amplifier U2B is connected to the output terminal of the short-circuit current collection circuit; The non-inverting input terminal of the second operational amplifier U2B is connected to a second threshold level setting circuit; the second threshold level setting circuit is used to provide a second threshold level to the non-inverting input terminal of the second operational amplifier U2B; The output end of the first operational amplifier U2A is connected to the output end of the second operational amplifier U2B to form the output end of the window comparator circuit; The first threshold level and the second threshold level are the two predetermined threshold levels, wherein the first threshold level is smaller than the second threshold level.

4. The charging short-circuit protection circuit according to claim 1, characterized in that: The digital logic control circuit includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an optocoupler chip U3, a JK trigger chip U4 and a reset button SW1; the first end of the eighth resistor R8 and the first end of the ninth resistor R9 are both connected to the VCC power supply; the second end of the eighth resistor R8 and the output end of the window comparator circuit are both connected to pin 2 of the optocoupler chip U3, the second end of the ninth resistor R9 is connected to pin 1 of the optocoupler chip U3, pin 3 of the optocoupler chip U3 is grounded, and pin 4 of the optocoupler chip U3 is connected in series with the tenth resistor R 10, the 4th pin of the optocoupler chip U3 is connected to the CLK1 pin of the JK trigger chip U4, the K1 pin, J1 pin, PR1 pin and VDD pin of the JK trigger chip U4 are all connected to the VCC power supply, the CLR1 pin of the JK trigger chip U4 is connected in series with the reset button SW1 and then grounded, the GND pin of the JK trigger chip U4 is grounded, and the Q1 pin of the JK trigger chip U4 is connected to the charging circuit switch protection circuit to realize the on / off control of the charging circuit switch protection circuit.

5. The charging short-circuit protection circuit according to any one of claims 1 to 4, characterized in that: The input end of the short-circuit current acquisition circuit also includes an input terminal H1, which has pin 1 and pin 2. Pin 1 of the input terminal H1 is connected to the sampling current outflow terminal IN-, and pin 2 of the input terminal H1 is connected to the sampling current inflow terminal IN+.

6. A low-speed two-wheel charging device, characterized in that: The low-speed two-wheel charging device is equipped with a charging short-circuit protection circuit according to any one of claims 1 to 5.

7. The low-speed two-wheel charging device according to claim 6, characterized in that: The low-speed two-wheel charging equipment is any one of a low-speed two-wheel charging pile, a low-speed two-wheel electric vehicle charger, and a low-speed two-wheel electric vehicle mobile charging vehicle.

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